This application requests funding to purchase a high-resolution Hitachi H-7650-II transmission electron microscope (TEM) and accessories for tomography and digital imaging. The H-7650-II will be housed in the Central Electron Microscope Facility (CEMF) at the University of Connecticut Health Center (UCHC), a central research facility supported by the Health Center Research Advisory Committee, extramural grants and user fees. The new TEM will replace one of the CEMFs two old and unreliable TEMs, providing capabilities not currently present in the facility. The operation of the H-7650-II will be managed by the PI and Co-Is, with oversight by an existing faculty advisory committee. The requested accessories include AMT XR-611 side mount and Advantage ERB bottom mount CCD cameras, an automatic tilt image acquisition system for tomography and Hitachi software for 3D reconstructions, cold finger, trackball stage control, multi-specimen holder, water recirculator and spare Wehnelt. A major user group of 15 NIH-funded scientists investigating the structure and function of supramolecular complexes, organelles, cells and tissues will account for approximately 80% of the instrument's use. Projects requiring tomographic analysis include structural analyses of flagellar dynein complexes, analysis of Herpes simplex virus portal rings, characterization of intracellular nanofabricated structures, correlation of 3D muscle sarcomere structure with 2nd harmonic images, analysis of membrane attachment sites of the bacterial cytoskeleton, and Golgi complex structure in exocrine secretory cells. Several projects will examine structural changes in regions of the nervous system of experimentally manipulated or genetically altered mice. Other projects will employ immunogold labeling of thin sections, negative stain immunolabeling of bacterial pili, and electron diffraction analysis of calcium phosphate crystals. As time permits, the instrument will be made available to other UCHC scientists. The proposed projects have relevance to a number of human conditions including early developmental defects, nervous system disorders such as epilepsy and multiple sclerosis, vascular disease, bladder dysfunction, inherited disorders of the craniofacial region, and bacterial infections. The digital cameras will facilitate rapid image acquisition and analysis, and the automated features of the H-7650-II make it an ideal instrument for a multiuser facility. The new TEM also will provide increased opportunities for training of students and young scientists through a graduate course in electron microscopy and hands- on experience during laboratory rotations and research fellowships. The UCHC administration is committed to providing state-of-the-art research facilities for its faculty. This is demonstrated by its commitment to provide a portion of the purchase cost of the instrument, to purchase instrument maintenance contracts, and to further upgrade the CEMF through the acquisition of ancillary preparative instruments. Public Health Relevance: Project Narrative Structural analyses of cellular and tissue components provide important information regarding normal function and pathological conditions. The high-resolution transmission electron microscope and accessories requested in this application will be used to a great extent in research projects investigating several disease-related phenomena. These projects include studies relevant to nervous system and cardiovascular diseases, cancer, inherited diseases, diseases of aging, and infectious diseases.